title: Microsatellite evolution: testing the ascertainment bias hypothesis.
abstract: Previous studies suggest the median allele length of microsatellites is longest in the species from which the markers were derived, suggesting that an ascertainment bias was operating. We have examined whether the size distribution of microsatellite alleles between sheep and cattle is source dependent using a set of 472 microsatellites that can be amplified in both species. For those markers that were polymorphic in both species we report a significantly greater number of markers (P < 0.001) with longer median allele sizes in sheep, regardless of microsatellite origin. This finding suggests that any ascertainment bias operating during microsatellite selection is only a minor contributor to the variation observed.
authors.affiliation: AgResearch Molecular Biology Unit, Centre for Gene Research and Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand. crawforda@agresearch.cri.nz
authors.forename: A M
authors.initials: AM
authors.lastname: Crawford
authors.forename: S M
authors.initials: SM
authors.lastname: Kappes
authors.forename: K A
authors.initials: KA
authors.lastname: Paterson
authors.forename: M J
authors.initials: MJ
authors.lastname: deGotari
authors.forename: K G
authors.initials: KG
authors.lastname: Dodds
authors.forename: B A
authors.initials: BA
authors.lastname: Freking
authors.forename: R T
authors.initials: RT
authors.lastname: Stone
authors.forename: C W
authors.initials: CW
authors.lastname: Beattie
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics*; D019143:Evolution, Molecular; D008040:Genetic Linkage; D005819:Genetic Markers; D006579:Heterozygote; D018895:Microsatellite Repeats; D008957:Models, Genetic; D011110:Polymorphism, Genetic; D012756:Sheep / Q000235:genetics*
chemical_list: D005819:Genetic Markers